Field of the Disclosure
This application generally relates to data distribution, data loss, recovery, reliable computing systems, distributed computing systems, and other matters.
Background of the Disclosure
In storage systems, it can sometimes occur that storage devices can lose data, or metadata, with the effect that data important to the user might be lost. In a storage system used with virtual machines (VM's), it can be advantageous to separate virtual storage devices (VSD's) from the devices that emulate them, real storage devices (RSD's). In such cases, users and their guest operating systems (guest OS's) perceive storage as unitary data blocks maintained reliably on the VSD's, while host operating systems (host OS's) and other system elements perceive both the VSD's, and also the RSD's used to emulate those VSD's. If an RSD loses all or part of a data block, and that discovery is not made until later, it can sometimes occur that reconstructing any particular VSD from RSD's known to have good data can be infeasible without assistance.
Each of these issues, as well as other possible considerations, might cause difficulty in aspects of operating computing systems, particularly in those computing systems in which virtual machines are implemented, or in computing systems making use of distributed resources.